It sounds like the title of a movie — “Mr Trump goes to Turtle Bay” — and the event certainly lived up to its billing. In September we heard the most uncompromising speech ever given at the UN General Assembly. In 1960 Nikita Khrushchev grabbed the world’s attention by banging his shoe on the desk. Donald Trump didn’t do that. When he wants to send a message, the President has a simple oratorical technique: if they don’t get it the first time, he repeats it. Again — and again.

The fundamental idea of what is already being called the Trump doctrine is sovereignty. In one fairly short speech, he used the word “sovereign” or “sovereignty” no fewer than 21 times. “In America, the people govern, the people rule, and the people are sovereign . . . In foreign affairs, we are renewing this principle of sovereignty.” Mr Trump’s other key concept is closely related to sovereignty: “The nation state remains the best vehicle for elevating the human condition.”

The Trump doctrine is based on the idea that sovereign nation states, acting together, can and should solve many of the world’s problems. But the multilateral institutions that these sovereign nation states create, such as the UN, are always their servants and never their masters. He quoted Truman: “The success of the United Nations depends upon the independent strength of its members.” Sovereign nation states can and do form permanent alliances, such as Nato, and temporary coalitions of the willing, which can and should promote ideas such as democracy, the rule of law and free markets. “But we do expect all nations to uphold these two core sovereign duties: to respect the sovereign interests of their own people and the rights of every other sovereign nation.”

The only nations that place themselves beyond the pale are the “small group of rogue regimes” that respect “neither their own citizens nor the sovereign rights of their countries”. When such rogue regimes refuse to respect the sovereignty of other nations, there is a clear case for intervention — but in the name of sovereignty rather than democracy or human rights. The President did not echo his predecessors’ vocabulary by speaking of an “evil empire” or an “axis of evil”, but he went further than they did in vowing retribution. If the United States were ever forced to defend itself or its allies against attack, Mr Trump declared, it would be entitled to “totally destroy” North Korea. He threatened to force not only North Korea but also Iran to give up nuclear weapons, if necessary by tearing up the Iran deal signed by his predecessor. He also threatened to force Iran to “stop supporting terrorists, begin serving its own people, and respect the sovereign rights of its neighbours” — though he was not specific about the means. In dealing with cross-border issues, the sovereignty principle also applies: the rights of sovereign nations not to suffer terrorist attacks or the costs of uncontrolled migration must be respected. The President singled out Venezuela’s “socialist dictatorship of Nicolas Maduro” for having “destroyed a prosperous nation by imposing a failed ideology that has produced poverty and misery everywhere it has been tried”. He declared that “we cannot stand by and watch” as Venezuelans starve. Here, the sovereignty principle is invoked against a regime that denies its own people’s sovereign rights. A state that denies such rights is therefore no longer entitled to sovereignty. On this basis, the US-led invasions of Afghanistan and Iraq were justified, as was the overthrow of Colonel Gaddafi in Libya.